Automatic air bleeder valve for hydraulic systems



July 27, 1954 R STEVENSON 2,684,684

AUTOMATIC AIR BLEEDER VALVE FOR HYDRAULIC SYSTEMS Filed Aug. 50, 1951 HmW k m ,2 4O -/3 I4 15 FIEE 33 I H I am Ill/m 20 34 27 INVENTOR.

RUBERT STEVENSON ATTURNEY Patented July 27, 1954 AUTOMATIC AIR BLEEDERVALVE FOR HYDRAULIC SYSTEMS Robert Stevenson, Barrington, R. I.,assignor to Anco, Inc., Providence, R. L, a corporation of Rhode IslandApplication August 30, 1951, Serial No. 244,311

3 Claims.

This invention relates to an automatic air bleeder valve for hydraulicsystems and more particularly to a mechanism for automatically allowingentrapped air or gases to escape from hydraulic systems such as areemployed in automobiles or machine tools.

One of the principal objects of the present invention is to provide anautomatic air bleeder valve in a hydraulic system to permit the escapeof the air which accumulates when liquid is added to the system.

Another object of the present invention is to provide an automatic airbleeder valve in a hydraulic system in which the initial supply ofhydraulic liquid becomes immediately operative without the necessity ofbleeding the far end of the system.

Still another object of the present invention is to provide an automaticair bleeder for hydraulic systems of machine tools wherein the hydraulicpressures vary widely, from low pressure when the machine tool isrunning idle to high pressures when the machine tool is running at rapidtraverse speeds and is heavily loaded.

Other objects of the present invention will be come apparent in part andbe pointed out in part in the following specification and claims.

In the past, hydraulic systems employed a fixed type bleeder valve. Itwas located in the end of the line and a wrench was used to open thevalve to allow air to escape. When liquid flowed out of the system, thewrench was again used to close the valve. The present invention obviatesthe use of manually employed wrenches or the like and permits thecontinuous and automatic escape of entrapped air which is a frequentsource of trouble in hydraulic systems.

Like reference numerals refer to like parts in the accompanying drawingsin which:

Figure l is a side elevational view of the new and improved automaticair bleeder valve for hydraulic systems.

Figure 2 is a longitudinal sectional view taken along line 22 of Figure1 looking in the direction of the arrows.

Figure 3 is a left hand end view of the new and improved automatic airbleeder for hydraulic systems.

Figure 4 is a right hand end view of the same.

Figure 5 is a perspective view partly in section of the valve piston.

Figure 6 is a longitudinal sectional view similar to Figure 2, showingthe valve piston at the opposite end of the stroke from that shown inFigure 2.

Referring to the drawing wherein a valve body, generally indicated byreference character l0, having its external surface in steppedformation, consists of hexagonal head I l adjacent a shoulder 12, withan intermediate section threaded as at 3, and reduced portion 14terminating in a tapered end 15.

Internally, valve body 10 has an axial bore starting at [6 and extendingthroughout its length. Said bore is of stepped diameter and includes acounterbore 11, an enlarged valve piston bore or cylinder l8 and abushing receiving recess 20.

A bushing 2| is provided having a driving fit, so as to be secured inbushing receiving recess 26. Bushing 2| is provided with a piston bore23, the back wall 24 of which has an air escape port 25.

A valve piston 26 having an annular external recess 21 adapted to housea neoprene or other type resilient annular sealing member 30 is providedwith a concaved recess 3! in one end and a counterbored spring retainingopening 32 in its other end. A spring 40 is provided in this springretaining opening 32, one end of this spring pressing against the base33 on one end and against base 34 of piston bore 23 on the opposite end.

In order to more clearly understand the principle upon which the presentinvention operates I will specify a few dimensions. It is to be clearlyunderstood that these dimensions are by way of example only and are notlimitations on the present invention. Enlarged valve piston bore i8 isassigned a dimension of 1.000". Piston sleeve surface 23 is assigned adiameter dimension of .950". Valve piston 26 is assigned a diameterdimension of .900. Two observations are presented. Air has negligibleviscosity. Hydraulic liquid possesses the property of relatively highviscosity.

In operation, tapered end I5 is inserted into the line of a hydraulicsystem. A conventional union (not shown) will unite threads l3, hencevalve body It, to the line.

In starting up the system air will escape between valve piston 26 andenlarged valve piston bore [8, past 0 ring 30 into piston bore 23 andout air escape port 25. Just as soon as liquid under pressure actsagainst concaved recess 3 I, valve piston 26 is moved rearwardly intothe position shown in Figure 6 wherein the liquid pressure will act on 0ring 30 forming a. liquid tight seal with piston bore 23.

In order for air to escape after the ring 30 forms a liquid tight seal,the piston 26 must return to the position shown in Figure 2 wherein noliquid is acting against concaved recess 3| with suflicient pressure tocause movement of valve piston 26. 0 ring 30 is then uneifected by theliquid pressure. Therefore, air may bypass around valve piston 26 ashereinbefore described.

In view of the foregoing description of the construction it willtherefore be seen that the invention provides an automatic air vent andliquid sealing valve which when installed in hydraulic systems willautomatically bleed entrapped air without loss of hydraulic liquid.

Having shown, described and illustrated a preferred embodiment of ourinvention, we do not wish to limit ourselves to the exact structureshown inasmuch as mechanical structural changes can be made withoutdeparting from either the spirit or scope of the invention.

What I claim is:

1. In an automatic air bleeder valve for hydraulic systems, a valve bodyprovided with means for attachment to a hydraulic line, said valve bodybeing provided with an axial bore, a counterbore contiguous with saidbore, an enlarged valve piston bore adjacent said counterboreterminating in a bushing receiving recess, a bushing having a pistonbore and an air escape port secured in said bushing receiving recess, avalve piston provided with a circular external recess housing an O ringadapted to cooperate with said enlarged bore and said valve piston bore,a spring retaining recess in said valve piston, a spring coactingbetween the bottom of said valve piston recess and the base of saidbushing bore and a concave recess in one end of said valve pistonadapted to be acted upon by the liquid under pressure in said hydraulicline.

2. An automatic air bleeder valve for hydraulic systems having incombination a body centrally apertured to present shouldered cylinderportions of progressively greater diameters from one end to the oppositeend, a bushing inserted and fixed in the cylinder portion of largestdiameter, said bushing having an outlet escape port and an internaldiameter slightly smaller than the diameter of the succeeding cylinderportion of the body, a piston movable lengthwise within said bushing andbody, said piston having a clearance within said bushing such that airbut not liquid may bleed past it, a sealing ring on said pistonpositioned to block the passage of air when the piston is moved into thebushing, but positioned to clear the bushing when the piston is movedinto the body cylinder portion, and a spring normally forcing saidpiston to a position where the sealing ring is without the bushing topermit the bleeding of air, but functioning when the piston is underhydraulic pressure to allow it to move into the bushing and to seal thesaid escape port.

3. An automatic air venting and fluid sealing valve for the purposedescribed, comprising a body member having a valve chamber formedtherein, a pressure port and an aligned venting port facing one anotherin opposite end walls of said chamber and communicating therewith, saidventing port being open to the atmosphere, a flow passage coaxial withsaid body member extending inwardly from one end thereof andcommunicating with said pressure port, a piston having a concaved recessat one end and slidable in side of said chamber for controlling the flowpassage, resilient sealing means encircling said piston and between thepiston and the side walls of said chamber, spring means within saidchamber having one end acting against said piston and the other endbearing against the vented end wall of the chamber, said piston andsealing ring being in such clearance relationship with the side walls ofsaid chamber as to normally permit passage of air therebetween yet beincapable of passage therebetween of a liquid, said piston being urgedby said spring means to normally occupy a first position against thepressure ported end wall of said chamber with the recessed end of saidpiston over said pressure port for enabling the free communication andventing of air from said how passage through said chamber to saidatmosphere vent and a second position for closing the communicationbetween said flow passage and said vent when the liquid pressure in theflow passage acting against the recessed end of the iston forces thepiston against the pressure of said spring means into a retractedposition to open said pressure port while simultaneously closing thecommunication between said flow passage and said vent by compression ofsaid sealing means against the side walls of said chamber and saidpiston.

References Cited in the file of this patent UNITED STATES PATENTS 56Number Name Date 1,690,032 Noble Oct. 30, 1928 1,747,456 Noble Feb. 18,1930 2,046,228 Wiedmann June 30, 1935

